1. Field of the Invention
The present invention relates generally to number and letter generating devices and, more specifically, to electronic computing devices which generate numbers and letters at random with and without independence between each number or letter as it is selected.
2. Description of the Prior Art
There are many situations in which it is desirable to be able to select numbers or letters at random. One major application is in the selection of lottery numbers. Different lotteries require varied selections of numbers and/or letters. At the present state of the art there are no easy-to-use lightweight devices which can perform this function. Lottery selections made simply by "thinking of a number" are hardly random since the chooser's prior experiences and prejudices will interfere with randomness. Many of the organizations which run lotteries still use the process of selecting marked balls from a tumbler to obtain randomness. General purpose computers may be programmed with random number generating algorithms for this purpose, however they are heavy, expensive and this application wastes their computing power.
A number of efforts have been made to provide random number selector systems; however, each has severe shortcomings. R. C. Lawlor, U.S. Pat. No. 3,612,845 provided a computer utilizing random pulse trains. In this circuit, noise signals from a diode and clock pulses from a clock pulse source are fed to input legs of a logic circuit such as an AND gate, causing pulses of various amplitudes to appear in the output of the circuit. Complex threshold circuits are then required to eliminate low level pulses leaving high level random pulses. Only one random output at a time is provided. S. Harrington, et. al., U.S. Pat. No. 4,151,404 provided a random digit generator which samples a random pulse output, displays that output, determines a second random number and adds it to the first and displays it. This system is clearly unsuitable to the present purpose because each output is inherently greater than the previous output and, therefore, while the first output is truly random, each succeeding output is not entirely random. T. Newman, U.S. Pat. No. 4,227,064, provided a lottery generating method and apparatus which requires a user to depress one pushbutton for each numeral to be randomly selected, whereas one button operation is clearly preferable. Also, each number is chosen independently of all previous choices, however, in some lotteries, no number may be selected twice.